1. Field of the Invention
This invention relates to an IC socket for supporting an IC on its supporting platform so that the IC is readily contacted with contacts.
2. Brief Description of the Prior Art
FIGS. 8 through 10 show a conventional IC socket including an IC supporting platform.
An IC supporting platform 2' has leg portions 3' extending downward in parallel relation. The leg portions 3' are inserted into a guide hole 4' formed in a socket body 1' and at the same time, outwardly facing retaining claws 3a' each formed on a lower end of each of the leg portions 3' is retained in the wall of the guide hole 4' in order to prevent the IC supporting platform 2' from escaping upwardly. Furthermore, the leg portions 3' also serve to allow vertical and horizontal movements of the supporting platform against a spring 5' in association with the spring 5' urging the supporting platform 2' upwardly while holding the supporting platform 2' in its uppermost position. The supporting platform 2' and the leg portions 3' are comprised of a unitary number of component parts integrally formed of a synthetic resin material. When an IC is placed on the supporting platform 2' and pushed down by a cover (not shown) mounted on the socket body 1', or by a robot, the supporting platform 2' is moved in the horizontal direction while being lowered integrally together with the leg portions 3' against the spring 5'.
On the other hand, contact portions 7' of contacts 6' are in engagement with positioning holes 8' formed in a marginal portion of the supporting platform 2' and orderly arranged in a row. When the supporting platform 2' is moved in the horizontal direction integrally together with the leg portions 3' in order to be brought into correspondence with the IC, the contact portions 7' are also displaced following the movement of the supporting platform 2'. As a result, a correct correspondence between each contact portion 7' and each IC lead can be obtained.
However, in the above-mentioned conventional IC socket, if a gap formed between the guide hole 4' formed in the socket body 1' and each of the leg portions 3' is small as shown in FIG. 8, the range of horizontal movement of the supporting platform 2' is extremely limited. On the contrary, if the gap between the guide hole 4' and each of the leg portions 3' is designed to be large in order to obtain a large amount of movement of the supporting platform 9' as shown in FIG. 9, the retaining claw 3' of the leg portion 3' will tend to escape from the guide hole 4' as shown in FIG. 10 when the supporting platform 2' is moved in the horizontal direction. If the retaining claw 3a' is designed to be large in order to prevent the afore-mentioned undesirable incident, the spring stroke of the leg portion 3' is required to be set long in view of the necessity of pushing the leg portion 3' into the guide hole 4' to cause it to be retained at the wall of the guide hole 4'. This results in an increased bulk of the socket as a whole.
Furthermore, an additional problem with this prior art IC socket is that the horizontal movement of the supporting platform with the IC placed thereon lacks smoothness and reliability due to elastic resistance of the leg portions and retaining resistance of the retaining claws, and as a result, proper contact between the IC leads and the contacts arranged at micro pitches becomes difficult to obtain.